Tracheotomy or endotracheal tube cuff

ABSTRACT

An inflatable cuff for use in combination with a ventilation tube inserted into the trachea of a patient, a major portion of the outer surface of the inflated cuff sealingly engages the trachea gently enough to avoid distortion of, or trauma to the sensitive trachea wall. The cuff is of flexible material having thickness between 0.005 and 0.01 inch and, when inflated outside the trachea, the cuff takes the shape of a right cylinder having essentially flat end walls with curved transition portions between the end walls and the straight cylindrical walls.

United States Patent 1 Goodyear 1 May 8, 1973 [54] TRACHEOTOMY ORENDOTRACHEAL TUBE CUFF [75] Inventor: Chalmers M. Goodyear, Coopersburg,Pa.

[73] Assignee: The Foregger Smithtown, NY.

[22] Filed: Mar. 19, 1971 [21] App1.No.: 126,207

Company, Inc.,

[52] US. Cl. ..l28/351, 128/349 B [51] Int. Cl. ..A6lm 25/00 [58] Fieldof Search ..l28/351, 348, 349 B,

[56] References Cited UNITED STATES PATIENTS 3,659,612 5/1972 Shileyeta] ..l28/35l 3,565,079 2/1971 Jackson 3,504,676 4/1970 Lomholt..2,792,837 5/1957 Kardos ..l28/35l OTHER PUBLICATIONS Cooper et al.,Surgery, Gyne, Obstet. Dec. 1969, V01. 129, pp. 1235-1241 J.A.M.A. Feb.2, 1970, Vol. 211, No.5, p. 759

Primary ExaminerDalton L. Truluck Attorney-Ronald B. Sherer, James C.Simmons and B. Max Klevit [57] ABSTRACT An inflatable cuff for use incombination with a ventilation tube inserted into the trachea of apatient, a major portion of the outer surface of the inflated cuffsealingly engages the trachea gently enough to avoid distortion of, ortrauma to the sensitive trachea wall. The cuff is of flexible materialhaving thickness between 0.005 and 0.01 inch and, when inflated outsidethe trachea, the cuff takes the shape of a right cylinder havingessentially flat end walls with curved transition portions between theend walls and the straight cylindrical walls.

8 Claims, 6 Drawing Figures PATENTEUHAY 8l975 SHEET 1 OF 2 IN VENT (11-hCfio/mens M Gooojear BY Z / ATTORNEX PATENTEDNAY' 81975 7 3,781,692

SHEET 2 OF 2 PRIOR ART ATTORNEY TRACHEOTOMY OR ENDOTRACHEAL TUBE CUFFBACKGROUND OF THE INVENTION The invention related to endotracheal andtracheotomy tube cuffs, and more particularly to a novel cuff which,when inflated, gently yet sealingly conforms to the trachea withoutinflicting trauma.

Modern endotracheal and tracheotomy tubes inserted into the trachea of apatient whose breathing is to be assisted are conventionally providedwith an in flatable cuff for closing off the tracheal passage around thetube to avoid leakage of air from lungs around the ventilation tube.Such cuffed tubes are in wide use. Recently, however, some seriousdisadvantages and dangers resulting from the use of conventional cuffshave been discovered and investigated.

Numerous cases have occurred where patients who have undergonerespiratory assistance and treatment for respiratory failure with theuse of conventional cuffed ventilating tubes have subsequently sufferedvarious serious lesions of the trachea including tracheal stenosis,tracheomalacia and localized tracheal erosion. There have even beencases of rupture of the trachea. The fact that lesions have occurred inthe area engaged by the cuff leads to the conclusion that pressure ofthe cuff against the trachea wall has been responsible for the damage byinflicting localized trauma on the tracheal wall. The pressure used toinflate conventional tube cuffs is of the order of 200 to 300 mm ofmercury. The high pressure is required just to inflate these cuffs totheir expanded contour which in longitudinal cross-section is an elipse.The trachea deforms quite easily, so it is understood such inflation ofthe cuff will distend the tracheal wall.

In many cases cuffed tubes are kept in place in the trachea for extendedperiods, sometimes as long as several months. But lesions have occurredeven when a cuffed tube had been used for only several days. lnjury hasoccurred even though great care has been taken to avoid over-inflationof the cuff and the cuff has been periodically deflated.

The damage has been very serious in many cases, and sometimes fatal.Within a period ranging from several weeks to some months afterrespiratory assistance through intubation has ceased, the lesions haveinterfered with breathing by obstructing the tracheal passage. Resectionof the trachea has been successfully performed in cases of severeobstruction, but many cases have probably been undiscovered until afterdeath or never discovered, since death might have been attributed toheart failure or other causes rather than to the real cause. Thisproblem of tracheal injury is summarized in an article appearing inAnnals of Surgery, Vol. 169, No. 3, Mar. 1969 entitled The Evolution ofTracheal lnjury Due to Ventilatory Assistance Through Cuffed Tubesz" APathologic Study by Doctors Joel D. Cooper and Hermes C. Grillo.

The fact that cuffed endotracheal and tracheotomy tubes are in suchgeneral use makes this problem a very serious one. Although attemptshave been made to solve the problem of localized injury to the tracheacaused by the use of cuffed tubes, no satisfactory solution has beenfound in the prior art.

US. Pat. No. 3,481,339 discloses a double-chambered cuff intended tosolve the problem of pressureinduced trauma on the tracheal wall byperiodically exerting higher and lower pressures. This double-chamberedcuff did not provide sufficient improvement over the prior art to gainacceptance.

An approach to solving tracheal damage is described by Doctors Joel D.Cooper and Hermes C. Grillo in an article in Surgery, Gynecology &Obstetrics, Vol. 129, pp. 1235-1241, Dec. 1969, entitled ExperimentalProduction and Prevention of Injury Due to Cuffed Tracheal Tubes. Inthis article the authors show and describe a low pressure cuff of verythin latex material. This cuff is operated at low pressures; however,because the walls of the cuff were extremely thin, it was possible tohave the cuff wall hemiate below the endotracheal tube when insertedinto the patients trachea and then when inflated, block the lower end ofthe endotracheal tube.

SUMMARY OF THE INVENTION In order to avoid the problems inherent inprior art cuffs for endotracheal or tracheotomy tubes it has been foundthat the wall of the cufi in contact with the surface of the tracheashould be of a flexible material having a thickness of between 0.005 and0.01 inches, and when inflated outside of the trachea, should be in theshape of a right cylinder having substantially flat parallel top andbottom walls with a curved-transition surface between the end walls andthe straight, axial wall of the cylinder. In longitudinal cross-sectionthe cylinder would appear as a rectangle with pronounced rounded comers.

Observing the above teachings will result in a cuff that creates thedesired sealing engagement with the trachea of a patient' at inflationpressures of between 10 and mm of mercury, as opposed to the prior artcuffs requiring 200 to 300 mm of mercury to expand them into sealingengagement. At these pressures the cuff will form a surface of contactwith the trachea for an area of the tracheal wall substantially equal tothe length of the cuff. Unlike the conventional cuff, which inflates toa normal contour substantially in the shape of a football under highpressure, the cuff of the invention inflates under low pressure to thesubstantially rounded end cylinder. The pressures used in inflating thecuff of the present invention need be only slightly greater than thatnormally present upon the trachea wall during assisted respiration; and,therefore, the trachea is not distended. Thus, the pressure inflates thecuff, but does not expand it beyond its normal shape.

Cuffs may be provided according to the invention either in the form of asingle-walled, unitary inflatable sleeve for sealed attachment directlyto the ventilating tube at both of sleeve ends or in a double-walledform, with an inner, cylindrical wall secured to the tube and an outerflexible and inflatable wall. In either embodiment, the outer cuff wallis of flexible, material having a thickness in the range of from about0.005 to 0.01 inch. While the material may be elastomeric such as latex,it need not be, since the cuff is only inflated, not expanded.

The cuff is inflated after the cuffed tube has been inserted into thetrachea by means of a smaller tube, or inflation hose, leading from thecuff to a source of air under the proper low pressure. A pilot balloonis provided in communication with the smaller hose to show that the cuffis inflated.

Clinical tests have shown that when cuffs according to the inventionhave been used, satisfactory ventilation can be accomplished withminimal trauma to the trachea.

It is accordingly the primary object of the invention to provide animproved cuff for use in combination with an endotracheal or tracheotomytube to avoid injury to the trachea.

A further object is to provide an inflatable cuff which will inflateunder low inflation pressure to sealingly conform to the trachea wallwithout distending the trachea.

It is another object of the invention to provide in combination with aventilating tube for a patient a cuff of thin flexible material,whereby, the cuff will gently engage substantially all of the tracheawall for a length substantially equal to the length of the cuff under aconstant low pressure only slightly above that in the trachea.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an overall view inperspective of an-endotracheal tube provided with a cuff according tothe invention.

FIG. 2 is a view in longitudinal cross-section of the cuff of FIG. 1,with the cuffinflated.

FIG. 3 is a view in cross-section of the cuff in place on a tube withthe cuff in its deflated state.

FIG. 4a is a cross-sectional schematic diagram of the tracheal portionof the human anatomy.

FIG. 4b is the trachea of FIG. 4a with an inflated prior art cuffinplace.

FIG. 4c is the trachea of FIG. 4a with an inflated cuff of FIG. 1 inplace.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,in which like parts are indicated by like reference charactersthroughout, a cuff generally designated and constructed according to theinvention is shown secured in place on a conventional endotracheal tubegenerally designated 1 1.

FIG. 1 shows the cuff 10 in its inflated state. A flexible inflationhose 12 of much smaller diameter than the tube 11 from a source of airunder pressure (not shown) leads to the cuff 10, for supplying air toinflate the cuff after the tube has been placed in position in thetrachea.

The inflation hose 12 is equipped with a pilot balloon l3, andterminates in a widened end portion at 14 for connection to a suitablenipple or the like at the source of air under pressure. The inflationhose 12 is shown with sections cut away, and it will be understood thatthe hose 12 is ofa suitable length to accommodate tube 11 in itsoperative position.

The tube 11 and the hose 12 may be of suitable plastic material of oneof the types known in the art, and may be transparent or opaquev Theseelements possess sufficient rigidity to retain their general cylindricalshape though they are flexible enough to be bent as needed for use, asshown by the way the hose I2 bends as it diverges from the tube II atpoint 15.

Referring to FIG. 2, the tube II will be seen to have a generallycylindrical passage 16 for the delivery of air, oxygen, or otherventilating gases to the patient, and inflation hose 12 has a generallycylindrical passage 17 for admitting air or othergases to the cuff 10.The passages 16 and 17 must, of course, remain unobstructed andsubstantially undiminished in cross-sectional area throughout theirlength to assure uninterrupted flow therethrough.

The cuff 10, as shown in FIGS. 1 and 2, has an elongated axiallyextending wall portion 20 which is cylindrical in shape when the cuff isinflated outside the trachea. The cylindrical wall portion terminates inflat, parallel end walls 19, 21 with rounded corners 26, 28. This outercontour of the cuff 10 is formed by the cuff wall 20, which has athickness in the range of from 0.005 to 0.01 inches. For best resultsclinical tests have shown that the thickness of the wall 20 should bebetween 0.006 and 0.009 inches. The cuff wall may be formed of latexrubber or of some other soft flexible material such as a plastisol.Because of its thinness the cuff wall 20 will inflate to conform to thetrachea under a very low pressure in the range of from 10-90 mm ofmercury. The normal operating pressure is from 40-50 mm Hg. However, thematerial will withstand greater pressure without rupture if accidentallysubjected to such greater pressure, or if in some very special casehigher inflation pressure is deemed desirable. The normal range ofpressures (4050 mm Hg) applied to inflate, the cuff I0 is substantiallyequivalent to that normally present on the trachea wall, so no damage tothe trachea or distortion of the trachea will result from the pressureof the cuff 10 against the trachea wall.

The thickness of the cuff wall 20 is critical. The wall 21 can beneither too thin nor too thick if the desired results are to beobtained. If the cuff wall 20 were thicker than 0.01 inches the pressurerequired to inflate the cuff would exceed that which is safe if damageto the trachea is to be avoided as has been the case with prior art highpressure cuffs. On the other hand, a cuff having an outer wall 20thinner than 0.005 inches would be flimsy and subject to rupture; also,since a cuff is normally positioned quite near the open end of atracheotomy or endotracheal tube through which gases are delivered to apatient, a cuff which was too thin (under 0.005 inches) would be likelyto be pushed downwardly over the open delivery end of the ventilatingtube and interfere with the passage of gases to the patient.

As best shown in FIG. 2 the outer wall 20 terminates in reduced diametercollar portions 22 and 23 at opposite ends of the middle, inflatableportion 20. These collar portions 22 and 23 generally conform to thesize of the ventilating tube 11.

In the embodiment of the cuff 10 shown in FIGS. 1 and 2 there is shown acylindrical inner endotracheal tube and adaptor sleeve 24, which may be,and preferably is, thicker than the cuff wall 20. The wall 20 issealingly secured to the adaptor 24 at the end portions 22 and 23 toprevent leakage of air. The cylindrical adaptor sleeve 24$ may suitablybe of rubber or a plastic material, and is of such a diameter to fitsnugly around the outside of the tube 11, to which it may be secured, asby adhesive, if desired.

The cuff 10 may alternatively be formed as a unitary member, having onlythe outer wall 20, the collars 22 and 23 of which are sealing secured toa tube 1 1. In this alternate embodiment the cuff would also have acylindrical wall 20 and flat end walls 19, 21 as illustrated.

The inflation hose 12 enters the cuff at the position 25 at the upstreamend portion 22 of cuff wall 20. Here the cuff wall is formed into anoutwardly extended portion for admitting the hose 12. The cuff wall 20and adaptor sleeve 24 are sealed to the hose 12 at the position 25 toprevent air leakage. Where the cuff 10 has only a single wall 20, thewall 20 is similarly formed at its end 22 to admit the hose 12 betweenthe wall 20 and the outer surface of the tube 11 and the place of entryis similarly suitably sealed against air leakage, with the hose 12 lyingdirectly against the tube 1 1.

As shown in FIG. 2 the end 27 of the inflation hose 12 is preferablymitered so that no sharp outer edge is presented at the hose end 27.This also provides a larger opening for entry of air into the interiorof the cuff 10.

The collapsed state of the cuff 10 is shown in FIG. 3 wherein it will benoted that the cuff has folds and convolutions. Thus, the deflated cuffis easily insertable into the trachea with the tube 11. Even if the cuff10 is located near the open delivery end of the tube 11 it is thickenough so that it will not be subject to stretching dangerously downwardto cover the end of the tube 10 in which position it could interferewith the supply of gases to the patient.

In clinical use the folded, convoluted cuff is inserted and inflated tonormal shape of FIGS. 1 and 2, but not expanded. Flat end walls 19, 21do not block tube 11, and the full axial length of cylindrical wall 20gently engages trachea.

The pilot balloon 13, as shown in FIGS. 1 and 2, must be responsive tothe low inflation pressure used to inflate the cuff 10 since its purposeis to indicate that the cuff 10 is properly inflated when the cuff isout of sight within the trachea. The pilot balloon 13 is preferablydiamond shaped in longitudinal cross-section but may be of some othersuitable shape as desired. At its ends the pilot balloon 13 tapers downto cylindrical sleeve portions 30 and 31 which are of suitable diameterto snugly engage the inflation tube 12, to which the end portions 30 and31 are preferably adhesively secured.

As shown in FIG. 4c the cuff of the present invention inflates tosealingly engage the tracheal wall without changing the shape of thetracheal wall. This sealing engagement is assured by having theinflatable wall 20 of cuff 10 constructed so as to form the cylindricalshape I of FIG. 1 when inflated outside the trachea. As shown in FIG. 4bprior art cuffs were expanded to distort the trachea and thereby formthe required air seal.

The inflation hose 12 may pass through the pilot balloon l3 and ifconstructed this way is formed with one or more small apertures 32through its wall. Preferably a pair of such apertures 32 allowcommunication between the internal passage 17 of the hose 12 and theinterior of the pilot balloon 13 whereby the pressure existing withinthe hose 12 (and hence within the cuff 10) is also experienced by thepilot balloon, which inflates in response to the pressure to indicatethat the cuff 10 is in its inflated condition.

It may be preferred that the delivery tube 12 not pass through the pilotballoon 13. In that case the portion of tube 12 between sleeves 30 and31 is eliminated.

Various modifications and substitutions within the sco e of theinvention will sug est themselves to those skil ed in the art, and theinven 1on is not limited to the preferred embodiment illustrated anddescribed. For example, a cuff according to the invention could beformed with a fluted outer wall, or with a shape otherwise differingfrom that illustrated without departing from the spirit and scope of theinvention. Also a portion of the inflation hose 12 might be replaced bya passage formed within the wall of the tube 1 itself.

Although illustrated in combination with a tracheotomy tube, thecombination of the cuff and manner of use of the cuff of the inventionwith an endotracheal tube will be obvious to those skilled in the art.

Iclaim:

1. In a ventilating tube for insertion into the trachea of a patientsaid tube having an inflatable cuff for sealingly engaging the tracheawhen inflated the im provement which comprises:

said cuff being of a flexible imperforate material the major portions ofwhich have a wall thickness of between 0.005 and 0.01 inches;

said cuff including means for inflating said cuff to a constant pressureof between 10 and millimeters of mercury thereby engaging said tracheawithout distorting the trachea;

said inflated cuff having a longitudinal cross-section in the shape of arectangle with pronounced rounded comers; whereby said cuff engages thetrachea along a substantial portion of its outer surface.

2. A cuffed ventilating tube according to claim 1 wherein the cuff isseparable from the ventilating tube.

3. A cuffed ventilating tube according to claim 1 wherein the cuff is anelastomeric material.

4. A cuffed ventilating tube according to claim 1 wherein said cuffachieves optimum shape and sealing characteristics at pressure ofbetween 30 and 50 mm of mercury.

5. An inflatable tracheotomy cuff for use in combination with aventilating tube for insertion into the trachea of a patient comprisingan elongated imper forate generally cylindrical ventilating tube adaptorof flexible material, overlying said adaptor and having a thickness ofbetween 0.005 and 0.01 inches, a flexible cuff wall means securing andsealing the ends of said cuff wall to said adaptor, means for inflatingsaid cuff, said outer cuff wall being adapted upon inflation thereof toa constant pressure of about 10 to 90 mm of mercury to assume the shapeof a cylinder with top and bottom ends generally perpendicular to thelongitudinal axis of said cylinder with an arcuate transition zonebetween the walls and the ends of said cylinder whereby said cuffsealingly conforms to the trachea along a substantial length of thetrachea without distorting the trachea.

6. An inflatable tracheotomy cuff as in claim 5, said cuff wall beingformed of expandable material.

7. The inflatable cuff of claim 5, wherein the material of said cuffwall and said adaptor is an elastomeric material.

8. The inflatable cuff of claim 5 wherein the means for inflating thecuff comprises a tube with an indicating device to show when the cuff isinflated.

1. In a ventilating tube for insertion into the trachea of a patientsaid tube having an inflatable cuff for sealingly engaging the tracheawhen inflated the improvement which comprises: said cuff being of aflexible imperforate material the major portions of which have a wallthickness of between 0.005 and 0.01 inches; said cuff including meansfor inflating said cuff to a constant pressure of between 10 and 90millimeters of mercury thereby engaging said trachea without distortingthe trachea; said inflated cuff having a longitudinal cross-section inthe shape of a rectangle with pronounced rounded corners; whereby saidcuff engages the trachea along a substantial portion of its outersurface.
 2. A cuffed ventilating tube according to claim 1 wherein thecuff is separable from the ventilating tube.
 3. A cuffed ventilatingtube according to claim 1 wherein the cuff is an elastomeric material.4. A cuffed ventilating tube according to claim 1 wherein said cuffachieves optimum shape and sealing characteristics at pressure ofbetween 30 and 50 mm of mercury.
 5. An inflatable tracheotomy cuff foruse in combination with a ventilating tube for insertiOn into thetrachea of a patient comprising an elongated imperforate generallycylindrical ventilating tube adaptor of flexible material, overlyingsaid adaptor and having a thickness of between 0.005 and 0.01 inches, aflexible cuff wall means securing and sealing the ends of said cuff wallto said adaptor, means for inflating said cuff, said outer cuff wallbeing adapted upon inflation thereof to a constant pressure of about 10to 90 mm of mercury to assume the shape of a cylinder with top andbottom ends generally perpendicular to the longitudinal axis of saidcylinder with an arcuate transition zone between the walls and the endsof said cylinder whereby said cuff sealingly conforms to the tracheaalong a substantial length of the trachea without distorting thetrachea.
 6. An inflatable tracheotomy cuff as in claim 5, said cuff wallbeing formed of expandable material.
 7. The inflatable cuff of claim 5,wherein the material of said cuff wall and said adaptor is anelastomeric material.
 8. The inflatable cuff of claim 5 wherein themeans for inflating the cuff comprises a tube with an indicating deviceto show when the cuff is inflated.